As the RIS phase shift \(\theta _n\)  is adjusted to benefit \(D\) , the phases of channels \(h_{SR}^{(n)}\)  and \(h_{RE}^{(n)}\)  for each \(n\in \lbrace 0,\ldots ,N\rbrace \) 
will be misaligned.
Similarly, the phases of \(h_{JR}^{(n)}\)  and \(h_{RE}^{(n)}\)  for each \(n\in \lbrace 0,\ldots ,N\rbrace \)  will also be misaligned. Consequently, \(H_{SE}\)  and \(H_{JE}\)  become complex Gaussian r.v.s, and
\(|H_{SE}|^2\)  and \(|H_{JE}|^2\)  become exponential r.v.s with parameters \({\lambda _{SE}}=\alpha \Gamma _0N\eta ^2\zeta _{RE}\zeta _{SR}\)  and \(\lambda _{JE}=(1-\alpha )\Gamma _0N\eta ^2\zeta _{RE}\zeta _{JR}\)  , respectively, following [1]}.
The PDF of \(|H_{XY}|^2\)  is thus expressed as
\(f_{|H_{XY}|^2}(x)&=\frac{1}{\lambda _{XY}} \exp {\left(-\frac{x}{\lambda _{XY}}\right)}.\) 
